My guess is that "listDeployed" only returns something if the app is deployed using the MainDeployer. An app deployed by copying to the deploy folder will not be returned. But I never verified this guess.

My guess is that "listDeployed" only returns something if the app is deployed using the MainDeployer. An app deployed by copying to the deploy folder will not be returned. But I never verified this guess.

Correct. The MainDeployer exposed through JMX is deprecated and only handles deployments directly deployed through it.

Yes, it can be used for deployment/undeployment of applications, however there haven't been any updates to 5.1 - so in case there are issues you should give AS6 a try. AFAIK you would need to have the following .jars as part of your client classpath: